xviii THE DARWIN CENTENARY. [April 23, 



does not and cannot have both parent and offspring to guide him 

 in his decision. It often happens that only a single individual is at 

 hand for description. This is especially the case in the study of 

 collections made under difficulties, where it has been possible to get 

 only one or two specimens of a kind. The judgment must control 

 in such studies of resemblances. But inasmuch as we associate the 

 idea of affinity with resemblance, the question kept arising in the 

 minds of some naturalists even in the time of Linnasus, if resem- 

 blance is the controlling factor in determining that two or more 

 individuals, however variant, belong to a given species, and if we 

 claim that a given species is a line of individuals related by descent, 

 what are we to say when we find two species very closely resembling 

 each other? Are they related also? And by descent? It is, in 

 short, impossible to keep the idea of relationship by consanguinity 

 out of the mind. It forces itself at some time or other upon every 

 student. Among those who were most embarrassed by this recur- 

 rent query which would not be silenced, was Buffon, the naturalist. 

 He appears to have been much troubled at different times by the 

 perplexing question which could be explained only on the basis of 

 transmutation, but he was not able to offer any suggestion as to 

 the origination of species, which could be well defended. For a 

 long time he sustained animated controversies with his contempo- 

 raries, but never to good advantage. Nor did Lamarck, another 

 naturalist of about the same period, succeed in impressing upon his 

 associates his views in regard to the mutability of species. He made 

 suggestion after suggestion as to some possible method by which 

 a change of conditions acting on the organism, could bring about 

 a change of form and structure. He constructed a fabric of hy- 

 potheses by which he endeavored to account for the origin of 

 species. But it is the concurrent testimony of all who have familiar- 

 ized themselves with his work, that in the shape in which he urged 

 it, it deserved a part of the ridicule with which it was ruled out 

 of court. Geoffroy de St. Hilaire held similar views, but he could 

 not convince his contemporaries that the suggestions were satis- 

 factory. The poet Goethe also was intensely interested in the dis- 

 cussion, especially that which took place between St. Hilaire and 

 Cuvier, and endeavored by his own writings to clear up many of 



